Rate of rise circuit contact



Nov. 6, 1945 .J. F. ROWE z-n-AL RATE OF RISE CIRCUIT CONTACT OPERATINGDEVICE Filed Aug. 10, 1944 Patented Nov. 6, 1945 RATE OF RISE CIRCUITCONTACT OPERATING DEVICE Julian F. Rowe and Jean E. Rowe, Stewart Manor,Long Island, N. Y.

Application August 10, 1944, Serial No. 548,916

15 Claims. (01. 200-140) The present invention relates to circuitcontact operating devices which respond in a desired predeterminedmanner to certain rates of rise of temperature.

' A general object of the invention is the provision of a simplified butrugged and easily manufactured rate of rise circuit contact operatingdevice characterized by a chamber containing a body of displaceableliquid and electrical circuit contact operating means buoyed by theliquid, which is efiicient in operation and readily maintained andprovides for simple adjustment for control of sensitivity, readyinspection of the interior and easy removal of parts for servicing.

A more specific object of the invention is to provide an efiicient rateof rise circuit contact ber for effectively operating or affecting in asimple manner electrical circuit contacts when sudden pressure changesof a predetermined nature are applied to a surface of the liquid from Ha so-called rate of rise detection system to cause inter-chamber flow ofliquid.

A further object of the invention is the provision of such device whichis readily adapted to use as a control in a fire detecting or alarmsystem or the electrical system of an irregularly operable lightdisplay, and the like; which is composed of a minimum number of partsreadily assembled in a manner whereby they cooperate in The inventionaccordingly comprises the features of construction, combination ofelements and arrangement of parts, which will be exemplified in theconstruction hereinafter set forth and the scope of the invention willbe indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawing, in

which:

Fig. 1 is an elevational section, with parts broken away, of anembodiment of the device of the present invention;

- Fig. 2 is a sectional view taken along line 2-2 of Fig. 1, showing atop plan view of the casing of the unit shown in Fig. 1;

Fig. 3 is a transverse sectional view of that embodiment, taken alongline 33 of Fig. 1;

Figs. 4 and 5 are views similar to Fi 3, with parts broken away, takenrespectively along lines 4-4 and 5--5 of Fig. 1; and

Fig. 6 is a plan view to reduced scale of a modified form of top chamberspacer.

Referring to the drawing like numerals identify like parts throughout.An embodiment of the invention, as shown in Fig. 1, preferably comprisesan inner tube I0 which may desirably be formed of any suitabletransparent material for purposes of inspection, such as glass, and anouter tube ll telescoped therewith and preferably formed of similarmaterial. The inner tube l0 may be of any suitable shape, such ascircular, elliptical, etc., in cross-section, and is substantiallyclosed at the top l2 with the latter provided with a hollow neck I 3having an airtight connection with a passage member such as the tube l4,communicating with an expansion chamber of any suitable type. The tubel4 may be extended as indicated to provide the expansion chamber, andmay be desirably of flexible construction so as to be manipulated in anysuitable manner, such as for the purpose of extending it around a roomwhen the device is used as a fire detecting system control. The tube I4is preferably provided near or adjacent the instrument with a bleed-offspout I5 which is preferably restricted in any suitable manner, such asby a plug N5 of any suitable filler material, such as soft twine, torestrict the rate of bleed-off flow of fiuid from the expansion chamberin a controlled manner and to provide for ready sensitivity adjustmentby the degree of packing of the filler [6. With the tube l5 formed ofreadily severable plastic material and with an elongated filler plug [6employed decrease of the degree of restriction of flow of fluidtherethrough may selectively be accomplished in an easy manner bycutting oil a portion of the end thereof to foreshorten the length ofthe passage restriction. If desired the end of tube l5 may be fittedwith a breather hood to serve as a dust guard.

The outer tube H is closed at the bottom i! as shown and is open to theatmosphere at or near its top, or above liquid level, and preferably isprovided with a top flange l8 for suitably loosely centering it andspacing it from a surto hold the casing tube I9, support plate- .22;jand1 cap 23 in their assembled positions. if desired the casing tube I 9may be held in posi- Ob liously,

tion between the base plate 22 and ca-p 23 by. any I 3 suitable mountingmeans in lieu of tie bolts 24-24, such as by a panel forsuspension ofthe unit on a wall, to which panel the base plate and cap may be affixedin any suitable manner, such as by screws, etc. The cap 23 may beprovided with any suitable means for support of the instrument, such asan integral flange 2-5, for mounting the instrument to a wall-supported.panel or the like. The cap 23 preferably is provided with a centralaperture surrounded by a boss 26 over which is snapped a flexible sleeve21 which suit ably anchors the tube I4 in position.

The inner tube I3 is suitably aligned and supported by means of a topspacer member 28 which, as shown in Fig. 4, may comprise a disc ofsuitable insulating material, preferably somewhat resilient, having asubstantially centrally located aperture snugly receiving the neck I 3and with its peripheral edge snugly engaged at Zihwith the inner wallsof the outer tube II, centering or properly aligning the inner tube I'llwithin the outer tube, providing a shock absorbertherebetween, andserving to prevent undesirable floating of tube Ill. The-top spacer 23is also provided with a plurality of passages or holes 30-30 which maybe-in the form of notches in the periphery thereof, as shown in Fig. 4,for reception and passage of hanger wires 3I3I which, being formed ofsuitable metallic material such as copper, also serve as conductors inthe electrical circuit. Three such wires may be provided, if it isdesired, to operate two signal devices, suchas a buzzer and a bell fromthe single control, with one wire being common to both circuits of thetwo signal devices, Tube II should have communication with theatmosphere above the level' of the liquid therein and this may beprovided as a passage or passages through spacer 28, such as by notches33-33, of sufiicient dimension to permit pressure of fluid in the outerchamber to be equalized to atmospheric pressure quite rapidly.

It may be desired to have the top spacer 28 form a tight seal in themouth of the outer tube II in and about the supporting wires 3I3I, andin such case, as proposed in Fig. 6, the top spacer 28 may be formed ofsponge rubber with undersized notches I3I3-I3I) formed in the peripherythereof snugly'to receive the wires 3I-3'I. 'That embodiment of the topspacer may be provided with a plurality of apertures 32-32 ofpredetermined dimension for regulation of escape of fluid from or intothe outer tube I I at its top or above the level of liquid in that tube.

A bottom spacer member 33 is positioned within the outer tube 5 I nearthe bottom thereof, and when it is desired to provide for relativelongitudinal adjustment of the tubes In and II, the periphery of spacer33 may be substantially snugly fitted to the inner walls of the outertube I I, but

bers" formed by the inner tube I0 and by the.

.space between the outer tube II and such inner tube it. Such structurealso permits ready removalof the outer tube II for servicing, such aschange-of liquid, cleaning, etc.

The bottomispacer 33, as shown in Fig. 5, is providedwith a centralaperture 36 which is in the shape of a cloverleaf to accommodate acluster-of the supporting circuit wires 3I3I with their surroundingflexible sleeves of insulation 31-31. The spacer 33 is also providedwith peripheral notches 38-38 through each of which passes one of thesupport wires 3.I. with its surrounding insulating sleeve 3'1. Thespaces 33 also supports the bottom edge of the-inner tube I0 and is.preferably provided for thatpurpose with; acircumferential groove 39 toreceive. that: edge, and likewise acts as a shock absorber between.tubes Ill; and II. The bottom spacer 33, which. provides the partitionbetween the inner and outer chamhers, is provided with passage. meanstopermit flow of liquid between said chambers. Such means may be aplurality of grooves 43-43 which, by proper dimensioning, may beutilized to control the rate of flow of liquid between the inner andouter chambers.

As shown in Fig. 1 the support wires: &I'-3-I are extended down betweenthe inner tube III. and the outer tube II: and, with their'surroundinginsulating sleeves 31-31, are led through the notches 38-38 in thebottom spacer 33 and are then turned back upon themselves to extendthrough the central aperture 36 up into the inner chamber. In the innerchamber the cluster of'support' circuit wires 3I-3I may, if desired, beprovided with a suitable insulating and tying means 4I which maycomprise a shortsleeve of insulating material about each wire 3 I withthese sleeves bundled together by means of a cord or the like. Upwardlybeyond the bundling and tying means M the circuit support wires 31-3 Iare provided with terminal portions 42-42 which, as shown in Fig. 1, maybe spread radially toprovide a seat for the circuit closing means,hereinafter described, and to assure its interception as it descends.The terminal portions 42-42 are preferably so shaped as to engage orsubstantially engage the inner walls of the inner tube II! to provideforproper relative centering or alignment of the parts and additionally,if desired; to provide a friction grip to aid in preventing floatingdisplacement of theinner tube ID.

The support circuit wires 3I3I are suitably suspended from any desiredmeans, such as anchoring means mounted on or in the cap 23'. Suchanchoring means may comprise a pair of bolts 43, 43 and a' relativelyshorter bolt 44 of similar construction, except for theirrelativelengths. As shown in Fig. 3 the elongated bolts 43, 43 may each besurrounded by a sleeve 45- seated in a bore extending through thebracketing flange 25 and a, boss 46 in the cap 23'. The belt 44 islikewise surrounded by a sleeve 4-1 which extends through a hole in thecover 23' and its bracketing flange 25. Each of the bolts 43, 43 and 44ispreferably provided withan aperture extending transversely through itsinner end to receive one of the support wires 3l-3l. Each of the outerends of the bolts 43, 43 and 44 are provided with elongated slots 48-48,each of which is adapted to receive an external circuit wire 49. A nut59 on each of the bolts completes the anchorage assembly and with thewires 3l-3I and 49-49 extending through their respective apertures,tightening up of the nuts 50-50 will cause the sleeves 45, 45 and 41 toclamp the wires in position.

The non-conducting liquid 35, which partially fills the chambersprovided within the inner tube l and between the inner tube [0 and theouter tube H, is of a well-known type used in oil circult-breakers orswitches and has high dielectric strength, high flash point, non-gummingand nonvolatile qualities, and is of a selected specific gravity whichwill obtain for the user a desired rate of flow under certain pressureconditions in a particular device of the invention. This body ofnon-conducting liquid buoys the contact operating means which may be afloat of any desired type located in either chamber and associated withsuitable means to operate contacts or, as preferred, may be a float ofconducting material such as a hollow metal ball or a hollow ball coatedwith conducting metal, located within the inner tube l0. The float 5!should have suflicient weight so that it submerges in the non-conductingliquid to a suflicient depth assuring circuit make-and-break below thesurface of the liquid for efiicient spark quenching and exclusion ofoxygen during switching operations efliciently to eliminate fire hazardand to assure long life of contact surfaces. Preferably the float orball 5| is of a diameter slightly less than the inside diameter of theinner tube l 0, but

greater than the spacing between the contacts 42-42 at their nearestapproach, and greater than the space between adjacent contacts and alsoany space between such contacts and. walls of the float-containingchamber. The employment of a float ball assures efficient making andbreaking of the circuits at the contacts 42-42 regardless of the numberthereof, such as three shown in the embodiment of the drawing. Further,as the level of the non-conducting liquid rises and lowers in the innertube I 9, in response to pressure changes produced in the expansionchamber, the ball 5| will roll evenly up and down the inner wallsthereof with a minimum of surface tension.

Preferably the base plate 22 of the casing structure is provided with abreather hole 52 for communication between the atmosphere and theinterior of the casing. If desired the flange 58 of outer tube I! may,instead of or in addition to having some clearance with respect tocasing tube i9, be provided with one or more notches, such as that shownat 53, or the like, to assure cooperative communication betweenatmosphere and the interior of the outer chamber.

In operation, when the embodiment of the invention shown in the drawingis employed, for example, in a fire detecting system with two alarmcircuits being connected to the three terminal bolts 43, 43 and 44, andwith one thereof serving as a. common conductor in both circuits, theerpansion chamber such as that provided by elongated, flexible tubing l4may be suitably arranged around a room in any desired advantageouslocation. Slow rates of change of temperature in the room tend to causeslow expansion or contraction of air in the tube 14, as the case may be,

but such slow changes in pressure are con'currently offset by seepage ofair through the bleeder tube l5 and do not affect the switchhereindescribed. However, when unusual rates of rise of temperature are causedby any unusual conditions such as a fire, rapid expansion of the air intube I4 will increase pressure more rapidly than air can pass throughbreather tube I5, and this would result in the application of pressureto the surface of the liquid in the inner-chamber I0 which is suificientto cause flow of liquid from the inner chamber through passages 4ll4ilinto the outer chamber, lowering the level of liquid in chamber [0 andpermitting the float or ball 5| to fall into contact with the circuitcontacts 42-42 thereby closing the circuits. It will be understood thatoperation of the device is not dependent upon the employment of only asingle body of liquid in the two chambers and a body of air in theexpansion chamber since obviously any expansible fluid medium may beused in the expansion chamber as desired and this may, if desired, applypressure to the surface of the liquid, as described, directly orindirectly through an intermediate medium such as another body ofimmiscible liquid, etc., all as will be apparent to those skilled in theart. For example, the main body of liquid 35 may be water with a body ofoil floated 0n the top thereof in the float chamber, with the body ofoil being of sufficient volume to assure circuit making-and-breaking inthe oil.

Sensitivity control or adjustment thereof may be accomplished by any oneor more of certain features described above. Perhaps the more importantof these is the degree of packing of the filler IS in the breather tubel5, i. e., the amount of constriction thereof, which governs the rate offlow of fluid from and to the expansion chamber. This in turn determinesthe rate of expansion, or construction as the case may be, at whichsulficient pressure change is developed in a liquid chamber to causesuch alteration of the level thereof as to affect circuit operatingmeans. The specific gravity of the liquid and size of interchamberpassages will also have a bearing on the sensitivity of the device; aswill also the freedom with which liquid is permitted to enter or leavethe storage chamber, such as the freedom with which the liquid ispermitted to displace fluid or air therein. Further, adjustment of thelevel of liquid in the float-containing chamber has a hearing on thesensitivity since by that means the distance between the normal positionof the float and the position at which it afiects the electricalcircuits can readily be altered to change the conditions necessary tocircuit-operation of the device.

It is to be understood that although interchamber flow may be providedonly by means of grooves 40-40 in the-lower spacer member 33, there maybe used advantageously instead or cooperatively apertures such as checkholes in the walls of the inner tube ID at the minimum level to whichthe surface of the liquid therein is to be depressed. The advantage ofthis modification lies in the assurance of sub-surface contact in theoperation of the switch. Although in the embodiment shown in the drawingthe contact-operating float is shown in the chamber in which pressurevariations are caused by a rate of rise detection system to displace orvary the amount of liquid therein, it is obvious that the float may be,if desired, located in th other or storage chamber either to closecircuits contacts as the float rises'therein, or to break a signalcircuit below liquid surface as such float rises. Further, the floatneed not,. though it preferably does, operate contacts in thefloatchamber but may, if. de-

sired; move an operating, member which in turn may externally affectcircuit contacts.

As suggested above the device of the present invention. may also beemployed for purposes other than in the control of fire detectingsystems; For example, it may be employed as a control for irregularswitching of circuits of display or advertising lighting devices withthe circuit wires thereof connected to relay means for heavy currentswitching and with the tube constituting the expansion chamber coiled upwithin the housing of the device, suitably connected to a bulb in thedisplay circuit,.and with the employment of suitable draft means orguards to cause irregular cooling of the expansion chamber.

It will thus be seen that the objects set forth above are efficientlyattained, and since certain changes may be made in the aboveconstruction and different embodiments of the invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingshall be interpreted as illustrative and not in a. limiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific-feature of the invention hereindescribed, and all statements of the scope of the invention which, as amatter of language, might be said to fall therebetween.

Having described our invention, what we claim as: newand desire tosecure by Letters Patent is:

1 A rate of rise circuit contact operating device comprising a liquidcontainer having at least two chambers, a non-conducting liquidpartially filling the chambers, communicating means between the chamberslocated below the surface of said liquid and constituting the only meansof communication between said chambers, electrical circuit contacts,means for afiecting the electrical circuit contacts buoyed by theliquid, and means for applyingsudden pressure changes from a rate ofrise detection system to the surface-of the liquid in one chamber tocause displacement thereof.

2'. A rate of rise circuit contact operating device comprising a liquidcontainerhaving at least two chambers, a non-conducting liquid partiallyfillin the chambers, a body of immiscible fluid compl'eting the filling,of one chamber and adapted to apply pressure to the liquid in thechamber to cause: displacement thereof, a partition segregating saidchambers above the liquid surface but provided with communicating meansbetween said chambers below said liquid surface means for applyingsudden pressure changes from a rate of rise detection system to thefluid, electrical circuit contacts in one chamber, and means buoyed bythe liquid for affecting the electrical circuit contacts when the liquidis displaced.

3. A rate of rise circuit .contact operating device comprising a liquidcontainer having at least two chambers, a non-conducting liquidpartially filling, the chambers, means for segregating said chambersabove the liquid surface, communicating meansbetweenthe chambers belowsaid liquid surface, means for applying sudden pressure changes from arate of rise detection system to the. surface of the liquid in onechamber to cause displacement thereof, electrical circuit contacts invthat chamber immersed. in said liquid when said: circuit. isqbroken andmeans buoyed by the liquid for affecting, the electrical circuitcontacts when theliquid is displaced. g

4. A rate of rise circuit contact operating device comprising a liquidcontainer havingv at least two chambers, one ofsaid chambers having anair space freely communicating with the atmosphere and the other chamberhaving a fluid space confined against free communication withtheatmosphere, a non-conducting liquid partially filling the chambers,communicating means between said chambers located beneath the surface ofsaid liquid, a body of immiscible fluid: completing the filling of onechamber and adapted to apply pressure to the liquid in the chamber tocause displacement thereof, means for applying sudden pressure increasesfrom a rate of rise detection system to the fluid, electrical circuitcontacts immersed in the liquid in that chamber, and means buoyed by theliquid for affecting the electrical alarm circuit contacts when theliquid is displaced.

5. A rate of rise circuit contact operating device comprising a liquidcontainer having atleast two chambers, a non-conducting liquid partiallyfilling the chambers, communicating means between the chambers locatedbeneath the surface of said liquid and constituting the onlycommunication between said chambers, regulating means for controllingthe rate of flow of liquid between the chambers, a body of immisciblefluid completing the filling of one chamber and adapted to applypressure to the liquid in the chamber to cause displacementthereof,means for applying sudden pressure increases from a rate of risedetection system to the fluid, electrical circuit contacts immersed inthe liquid when said circuit is broken, and means buoyed by the liquidfor affecting the electrical circuit contacts when the liquid isdisplaced.

6. A rate of rise circuit contact operating device comprising a liquidcontainer having at least an inner and an outer chamber of transparentmaterial, a non-conducting liquid partially filling the chambers,communicating means between the chambers located wholly beneath thesurface of said liquid and constituting the only communication betweensaid chambers, a'body of immiscible fiuid completing the filling of theinner chamber and adapted to apply pressure to the liquid in the chamberto cause displacement thereof, means for applying sudden pressureincreases from a rate of rise detection system to the fluid, electricalcircuit contacts immersed in the liquid when said circuit is broken,means buoyed by the liquid for affecting the electrical circuit contactswhen the liquid is displaced to a certain critical level, and means forregulating liquid displacement to the critical level. V

7. A rate of rise circuit contact operating device comprising a liquidcontainer having at least two chambers, a non-conducting liquidpartially filling the chambers, communicating means between the chamberslocated beneath the level of said liquid and constituting the only meansof communication therebetween, a body of immiscible fluid completing thefilling of one chamber and adapted to apply pressure to the liquidtherein to cause liquid displacement, means for applyingv sudden.pressure increases from a rate of rise detection system to the fluid,electrical circuit contacts immersed in the liquid when said circuit isbroken, means buoyed by the liquid for closing the electrical circuitcontacts when the liquid is displaced from an initial level to a certaincritical level, and means for adjusting the initial level of the liquid.

8. A rate of rise circuit contact operating device comprising an outerchamber, a tube positioned in said outer chamber and constituting aninner chamber, means closing the bottom of said tube and provided with apassage for interchamber communication, a body of non-conducting liquidpartially filling said chambers and covering said passage, a float insaid inner chamber buoyed by said liquid, a rate of rise means connectedto the upper portion of said tube and containing an immiscible fluidadapted to apply pressure to the surface of the liquid in said chamber,and contacts for an electrical circuit controlled by movement of saidfloat.

9. A rate of rise circuit contact operating device comprising an outerchamber; a tube positioned in said outer chamber and constituting aninner chamber; a body of non-conducting liquid partially filling saidchambers; means for spacing the upper part of said tube from the wallsof said chamber; means for closing the bottom of said tube, spacing itfrom the walls of said outer chamber, having openings to allow circuitwires to enter the bottom of said tube and to pass between the tube andthe walls of said outer chamber, and having a passage for inter-chambercommunication; a float in said inner chamber buoyed by said liquid; arate of rise means connected to the upper portion of said tube andcontaining an immiscible fluid adapted to apply pressure to the surfaceof the liquid in said tube; and contacts for an electrical circuitcontrolled by movement of said float.

10. A rate of rise circuit contact operating device comprising an outerchamber; a tube positioned in said outer chamber and constituting aninner chamber; a body of non-conducting liquid partially filling saidchambers; means for spacing the upper part of said tube from the Wallsof said chamber; means for closing the bottom of said tube, spacing itfrom the walls of said outer chamber, having openings to allow circuitwires to enter the bottom of said tube and to pass between the tube andthe walls of said outer chamber, and having a liquid passage forinterchamber communication; a float in said inner chamber buoyed by saidliquid; a rate of rise means connected to the upper portion of said tubeand containing an immiscible fluid adapted to apply pressure to thesurface of the liquid in said tube; contacts for an electrical circuitcontrolled by movement of said float; and means for adjusting therelative heights of the inner and outer chambers.

11. A rate of rise circuit contact operating device comprising an outerchamber of transparent material, a tube of transparent materialpositioned in said outer chamber in adjustable relation thereto andconstituting an inner chamber, means closing the bottom of said tube andprovided with a passage for filter-chamber communication, a body ofnon-conducting liquid partially filling said chambers and covering saidpassage,

a float in said inner chamber buoyed by said liq uid, a rate of risemeans connected to the upper portion of said tube and containing animmiscible fluid adapted to apply pressure to the surface of the liquidin said tube, and contacts for an electrical circuit controlled bymovement of said float.

12. A rate of rise circuit contact operating device comprising an outerchamber; a. tube of insulating material positioned in said outer chamberand constituting an inner chamber; a body of non-conducting liquidpartially filling said chambers; means for spacing the upper part ofsaid tube from the walls of said chamber; means for closing the bottomof said tube, spacing it from the Walls of said outer chamber, andhaving a liquid passage for inter-chamber communication; circuit wirespassing down between said tube and the walls of said chamber and throughsaid bottom spacer to support the latter and said tube, said wiresterminating in circuit terminal portions in said tube; a rate of risemeans connected to the upper portion of said tube and containing animmiscible fluid adapted to apply pressure to the surface of the liquidin said tube and depress the level thereof by displacement; and anelectrically conducting float in said tube buoyed by the liquid forclosing an electrical circuit connected to said Wires when the level ofsaid liquid is depressed.

13. A rate of rise circuit contact operating device comprising an outerchamber, a tube positioned in said outer chamber and constituting aninner chamber, means providing substantially free communication betweenthe atmosphere and the upper portion of said outer chamber, meansconfining the upper portion of the inner chamber against freecommunication with the atmosphere, means closing the bottom of said tubeand provided with a passage for inter-chamber communication, a body ofnon-conducting liquid partially filling said chambers, an electricallyconducting float in said inner chamber buoyed by said liquid, a rate ofrise means connected to the upper portion of said tube and containing animmiscible fluid adapted to apply pressure to the surface of the liquidin said tube, electrical circuit contacts mounted in said tube forcontact by said float upon depression of the liquid and immersed in thelatter when said circuit is broken, and means for adjusting the relativeheights of the inner and outer chambers.

14. A rate of rise circuit contact operating device comprising an outerchamber of transparent insulating material, a tube of transparentinsulating material positioned in said outer chamber in adjustablerelation thereto and constituting an inner chamber, a body ofnon-conducting liquid partially filling said chambers, means for spacingthe upper part of said tube from the walls of said outer chamber; meansfor closing the bottom of said tube, spacing it from the walls of saidouter chamber, and having a liquid passage for interchambercommunication; circuit wires passing between the tube and the walls ofsaid outer chamber through said bottom spacer and up into said tube,said wires supporting said spacer and tube and said wires beingconnected to terminal means beneath the normal surface of the liquid; anelectrically conducting float in said inner chamber buoyed by saidliquid for circuit-closing contact with said terminal means upondepression of the liquid surface from an initial level; a rate of risemeans connected to the upper portion of said tube and containing animmiscible fluid adapted to apply pressure to the surface of the liquidin said tube for depression thereof; and means for adjusting therelative heights of the inner and outer chambers for altering theinitial liquid level.

15. A rate of rise circuit contact operating device comprising an outerchamber; a tube of insulating material positioned in said outer chamberand constituting an inner chamber; a body of non-conducting liquidpartially filling said chambers; means for spacing the-upperwpart of"saidztube from the Walls of saidchamber; means cation; circuit wirespassing down between said tube-"andthe walls of said ch'am ber'andthrough saidbottom spacertd support the latter andsaid tube; said Wiresterminating-,lin oircuit terminal portions in said :tube'lrictionallygrippingv the inupper. portion of said tube and 'containing an'immiscible fluid adapted'to' applypressure to the surface of "the liquidin said tube'and depress the ner walls thereof beneath the-normalsurface of Y level thereof by displacement; and an electricallyconducting fioatin' said tube buoyed by the liquid" for'closinganelectrical circuit connected to said wires when the level'of said liquidisdepressed.

JULIAN F. ROWE; JEANE; ROWE.

